Configuring Entities

An entity is a lightweight persistence domain object. Typically, an entity represents a table in a relational database, and each entity instance corresponds to a row in the table. The primary programming artifact of an entity is the entity class, although entities can use helper classes.

The persistent state of an entity is represented either through persistent fields or persistent properties. These fields or properties use object/relational mapping annotations to map the entities and entity relationships to the relational data in the underlying data store.

Identifying an Entity

Use the @Entity annotation to specify that a class is an entity, as shown in the following example:

@Entitypublicclass Employee implementsSerializable{
...
}

Note: The entity class must also be listed in your persistence.xml file. An entity can also be defined using the orm.xml <entity> tag.